Steel SK5 Annealed vs SK5-HR
Steel · SK5 temper comparison
SK5 Annealed and SK5-HR are two conditions of the same steel grade, SK5: Annealed versus HR (hot rolled). The chemistry is identical, so every difference below comes from the condition. SK5-HR is the stronger of the two: yield strength 400 MPa (58 ksi) against 380 MPa (55.1 ksi) for SK5 Annealed, about 5% more; tensile strength follows at 710 MPa (103 ksi) vs 640 MPa (92.8 ksi). In exchange, SK5 Annealed is the more ductile: elongation 20% versus 12% for SK5-HR, and SK5-HR is harder (200 HB vs 185 HB). SK5 Annealed runs hotter in service (400°C vs 350°C continuous).
SK5 AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
SK5-HRChoose it when strength drives the design.
SK5 Annealed vs SK5-HR: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 720 MPa104 ksi · Shear Strength 460 MPa66.7 ksi
Physical
Density and transition temperatures.
Same in both: Density 7.82 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,470°C2,678 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 48 W/m·K27.7 BTU/hr·ft·°F · Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 9.5 % IACS · Electrical Resistivity 1.8×10⁻⁷ Ω·m7.09 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 18 / 100 · Castability 30 / 100 · Brazeability / Solderability 45 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 27 MJ/kg11,608 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 30%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
SK5 Annealed vs SK5-HR — frequently asked
Is SK5-HR stronger than SK5 Annealed?
Yes. SK5-HR has a typical yield strength of 400 MPa (58 ksi) against 380 MPa (55.1 ksi) for SK5 Annealed — about 5% more. Tensile strength is 710 MPa (103 ksi) vs 640 MPa (92.8 ksi).
Which condition does FabDigit quote by default, Annealed or HR?
HR is the default SK5 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, SK5 Annealed or SK5-HR?
SK5 Annealed, by a small margin. Both rate fair for machinability — 42/100 against 36/100 for SK5-HR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SK5 Annealed and SK5-HR side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.